Communication is an essential and integrated part of power converters. This communication needs to be robust and reliable, and with rather low latency. A control unit needs to communicate with several or even hundreds of units or more building blocks/cells/power modules. Communicating units may be placed at different potentials (several kilovolts plus), requiring electrical isolation between the transmitters and receivers.
A traditional solution to this communication problem has been the use of optical fibres, which can provide sufficiently low latency, adequate data rates, and also electrical isolation. A problem with these optical components is that their performance deteriorates over time. Moreover, they also require substantial installation efforts, and some space for the cables which may not always be available, resulting in damage caused by excessive bending, etc.
State of the art solutions typically apply                fibre optics, which are expensive and deteriorate over time, and require time consuming installation        other optical solutions like free-space optics alone or in combination with wired communications like for instance Ethernet or EtherCAT or similar, where the free space optics part provides the electrical isolation.        
Jong Ho Kim et al: “Antenna directivity effect on the delay spread at millimeter-wave”, ADVANCED COMMUNICATION TECHNOLOGY (ICACT), 2011 13th International conference on, IEEE, (2011-02-13), pages 8-12, presents a delay spread characteristics at millimeter-wave band study.
It has been proposed the use of wireless control of power network switching devices in US2012207138.